High-bandwidth multi-band antenna

ABSTRACT

A high-bandwidth multi-band antenna includes a ground plane member, a first patch member extending in generally-parallel spaced relationship with the ground plane member and electrically connected thereto, and a second patch member connectable to a signal feedline and extending generally coplanar with the first patch member within a slot formed in the first patch member. The second patch member is formed integral with a vertical conductive connecting member as part of a folded conducting plate; this construction allows the second patch member to be quickly and accurately positioned relative to the ground plane member before attachement to the ground plane member. The antenna has the advantages of a high bandwidth, simple construction and inexpensive manufacture.

The present invention relates to a multi-hand antenna, and moreparticularly to a high-bandwidth multi-band antenna that is both compactand easy-to-manufacture.

Because of their compactness, ease-of-manufacture and relatively lowcost, microstrip antennas have become widely used as vehicle antennasfor mobile telephones. Microstrip antennas generally consist of agrounded patch member that extends in parallel spaced relationship withone or more other patch members, with a signal feedline extending to theplane of those other patch members. Many such antennas are designed asdual-band antennas, in which the return loss decreases in two separatedfrequency bands each used for a different phone system. Although suchantennas are already of relatively simple construction, efforts continueto improve them, both by simplifying their design and reducing theirmanufacturing cost.

The inventors of the subject invention have found that the bandwidth ofa microstrip antenna can be generally increased if the antenna isconstructed such that a signal feedline extends into the plane of theother patch members so as to be separated by a slot from one of theother patch members which is electrically connected to the groundedpatch member of the antenna.

The inventors have also found a way to further simplify the constructionof such microstrip antennas when the further patch members extend in adifferent plane from the grounded patch member, as is the case with oneform of the subject invention. Microstrip antennas of that type areusually constructed by first forming a grounded patch member separatelyfrom the one or more further patch members, and then forming an antennasuch that all of the patch member are maintained in a generallymulti-planar parallel spaced relationship. For final assembly of theantenna, the patch members need to be held in a multi-planar parallelspaced arrangement at an appropriate orientation. It has been found thatforming the further patch members so as to have an attached integralspacing means prior to final connection with the grounded patch memberallows the further patch members to be more quickly positioned relativeto the grounded patch member during final assembly.

In a first aspect, the subject invention is a high-bandwidth multi-bandantenna that includes: a grounded patch member, a further patch memberextending in generally-parallel spaced relationship with the groundedpatch member and being electrically connected thereto by a radiatingelement, and a feedline capacitively coupled to the further patchmember.

In a second aspect, the subject invention is a high-bandwidth multi-bandantenna, including: a grounded patch member, a further patch memberextending in generally-parallel spaced relationship with the groundedpatch member and being electrically connected thereto, and a feed meansadapted to carry a feedline signal. The feed means terminates generallycoplanar with the further patch member and occupies a part of a voidspace in the further patch member, a slot being thereby defined betweenthe further patch member and the termination. The further patch memberand the termination are capacitively coupled across the slot.

In a first form of the second aspect of the invention, the teed meansmay be a feed patch member, with the dimensions of the feed patch memberand the width of the slot being selected such that each is within arespective range in which the bandwidth of the antenna varies with theslot width. In a second form of the second aspect of the invention, theantenna may also include a discrete capacitor connected between the feedmeans and the further patch member, wherein the antenna bandwidth varieswith the capacitive value of the discrete capacitor. In this second formof the second aspect of the invention, the feed means may be an endportion of a feedline carrying the feedline signal.

In the first and second forms of the second aspect of the invention, thefurther patch member may be electrically connected to the grounded patchmember by a radiating element extending between the grounded patchmember and one first edge of the further patch member, and morepreferably a first edge of the radiating element may be connected to theone first edge of the further patch member. The whole first edge of theradiating element may be connected to the whole one first edge of thefurther patch member such that the connecting edges are coextensive, oralternatively, the whole first edge of the radiating element may beconnected to only a portion of the one first edge of the further patchmember, and in such case, the feed means may extend inwardly from anunconnected portion of the one first edge of the further patch member.

In one form, the further patch member and the radiating element may beintegrally formed from a conductive sheet, and separated by a fold-linein the sheet. In this form, the radiating element preferably extendsgenerally normal to the further patch member, and more preferably, theradiating element is generally-planar; even more preferably, this formalso includes a solid dielectric material extending in the space thatseparates the grounded patch member from the further patch member andthe feed means. In another form, the further patch member, the radiatingelement and the grounded patch member may be integrally-connected partsof a generally-planar conductive sheet.

In the first form of the second aspect of the invention, the groundedpatch member, the further patch member and the feed patch member may beeach formed as a conductive surface on a dielectric support. In thisform of the invention, the further patch member and feed patch membermay both have a rectangular shape with longer first edges of each beingoriented in the same direction. The length and width of the furtherpatch member may be approximately five times the respective length andwidth of the feed patch member. Also in this form of the invention, afrequency bandwidth for a higher one of the resonant frequencies of theantenna may increase with a reduction in the length of the further patchmember. A lowest resonant frequency of the antenna may decrease with areduction in the length of the further patch member.

The resonant frequencies of the antenna may increase with an increase inthe width of the radiating element. The radiating element may beapproximately 25 mm wide. A decrease in height of the radiating elementmay result in an increase in the resonant frequencies of the antenna.

The further patch member may be approximately 45 mm long and 24 mm wide,and in such case the feed patch member is preferably approximately 9 mmlong and 5 mm wide. More preferably, a slot formed between the furtherpatch member and feed patch member has a width between approximately 0.5mm and approximately 1 mm.

The radiating element may include a series of parallel strips, eachstrip extending between the grounded patch member and the one first edgeof the further patch member.

Preferably, the antenna operates, in a first band in the range of 900MHz and in a second band in the range of 1800 MHz. More preferably, italso operates in a third band in the range of 2100 MHz.

In the first form of the second aspect of the invention, the antenna mayalso include a radiating element connecting a portion of an edge of thegrounded patch member to a portion of an edge of the further patchmember such that the grounded patch member, radiating element andfurther patch member form a generally U-shaped configuration. Thegrounded patch member, further patch member, feed patch member andradiating element all extend in the same plane.

Preferably, the antenna may also include a feedline patch memberconnected to the feed patch member. The feedline patch member extendsgenerally parallel to the radiating element and toward the groundedpatch member in the plane of the further patch member, feed patch memberand radiating element. More preferably, the grounded patch member,further patch member feed patch member, feedline patch member andradiating element are each formed as a conductive surface on adielectric support. Even more preferably, the dielectric support isformed from one of FR4, polyester film, glass and duroid.

The word ‘radiating’ in the term ‘radiating element’ is not intended todenote an antenna that is only in a transmitting state, but rather isused to describe that this portion (‘the radiating element’) of theantenna is active whenever the antenna is active, i.e. during receptionas well as transmission.

Preferred features of the present invention will now be described, byway of example only, with reference to the accompanying drawings, inwhich:—

FIG. 1 is a perspective view of a first embodiment of the antenna of thesubject invention;

FIG. 2 is a plan view of the antenna of FIG. 1;

FIG. 3 is a perspective view of a second embodiment of the antenna ofthe subject invention;

FIG. 4 is a perspective view of a third embodiment of the antenna of thesubject invention;

FIG. 5 illustrates a typical surface current distribution pattern forthe antenna of FIG. 1;

FIG. 6 is a graph illustrating the S11 return loss versus frequency forthe antenna of FIG. 1;

FIG. 7 in a graph illustrating the input resistance and impedance versusfrequency for the antenna at FIG. 1;

FIG. 8 is a graph illustrating variation in the S11 return loss withfrequency for variation in the length of the first patch member of thefirst embodiment of the antenna;

FIG. 9 illustrates the vertical-polarisation radiation pattern formed inthe polar azimuth XY plane of the antenna of FIG. 1;

FIG. 10 illustrates the vertical-polarisation radiation pattern formedin the polar elevation XZ plane of the antenna of FIG. 1;

FIG. 11 illustrates the vertical-polarisation radiation pattern formedin the polar elevation YZ plane of the antenna of FIG. 1;

FIG. 12 is a schematic plan view of the further and feed patch membersof an antenna of the second embodiment that was used in a parametricstudy, the view indicating the dimensions (in millimetres) of the firstand second patch members;

FIG. 13 is a graph illustrating variation in imaginary impedance withfrequency for variation in the length of the further patch member in theparametric study;

FIG. 14 is a graph illustrating variation in real impedance withfrequency for variation in the length of the further patch member in theparametric study;

FIG. 15 is a graph illustrating variation in the S11 return loss withfrequency for variation in the length of the further patch member in theparametric study.

FIG. 16 is a graph illustrating variation in the S11 return loss withfrequency for variation in the height of the radiating element and thelength of the signal feedline between the grounded patch member and thefurther patch member in the parametric study;

FIG. 17 is a graph illustrating variation in imaginary impedance withfrequency for variation in the width of the radiating element in theparametric study;

FIG. 18 is a graph illustrating variation in real impedance withfrequency for variation in the width of the radiating element in theparametric study;

FIG. 19 is a perspective view of a fourth embodiment of the antenna ofthe subject invention, the fourth embodiment being the same as the thirdembodiment except for the radiating element being formed by a series ofstrips;

FIG. 20 is a perspective view of a fifth embodiment of the antenna ofthe subject invention, this embodiment using a discrete capacitor;

FIG. 21 is a graph illustrating variation in the return loss withfrequency for the fifth embodiment of the antenna;

FIG. 22 is a plan view of a sixth embodiment of the antenna of thesubject invention, this embodiment showing an antenna in which thegrounded patch member, further patch member and feed patch member areall coplanar;

FIG. 23 is a plan view of a seventh embodiment of the invention, thisembodiment being the same as the sixth embodiment except for thelocation of the radiating element between the grounded patch member andthe further patch member;

FIG. 24 illustrates the antenna of FIG. 22 in a proposed application asa roofmount antenna;

FIG. 25 illustrates the antenna of FIG. 22 in a proposed application asa windscreen antenna;

FIG. 26 is a return-loss measurement in freespace for the antenna ofFIG. 22;

FIG. 27 are radiation pattern measurements in freespace for the antennaof FIG. 22, one radiation pattern being for a lower frequency of 960 MHzand one radiation pattern being for a higher frequency of 1795 MHz;

FIG. 28 is a return-loss measurement for the antenna of FIG. 22 whenroof-mounted;

FIG. 29 is a radiation pattern measurement for lower band frequency forthe antenna of FIG. 22 when roof-mounted;

FIG. 30 is a radiation pattern measurement for upper band frequency forthe antenna of FIG. 22 when roof-mounted;

FIG. 31 is a return-loss measurement for the antenna of FIG. 22 wheninstalled on a vehicle windscreen;

FIG. 32 are radiation pattern measurements for the antenna of FIG. 22when installed on a vehicle windscreen, the lower frequency measurementbeing at 890 MHz and the upper frequency measurement being at 1750 MHz;

FIG. 33 is a return-loss measurement for the antenna of FIG. 22 wheninstalled on a vehicle bumper;

FIG. 34 are radiation pattern measurements for the antenna of FIG. 22when installed on a vehicle bumper, the lower frequency measurementbeing at 925 MHz and the other measurement being at a referencefrequency; and,

FIG. 35 is a radiation pattern measurement for the antenna of FIG. 22when installed on a vehicle bumper, the upper frequency measurementbeing at 1795 MHz and the other measurement being at the referencefrequency;

FIG. 36 is a perspective view of a eighth embodiment of the antenna ofthe subject invention, the embodiment being similar to the thirdembodiment shown in FIG. 4 and the fourth embodiment shown in FIG. 19;and,

FIG. 37 is a plan view of the antenna of FIG. 36.

The antenna of the invention is designed to operate over two or threefrequency bands. One example of its use would be in a multi-bandtelephone antenna to cover the bands: 890 to 960 MHz, 1710 to 1880 MHz,and 1920 to 2175 MHz. The upper two of these three bands could becombined into a very wide single band. Being compact and inexpensive tomanufacture, this antenna is equally useful for other communicationapplications.

As illustrated in FIG. 1, the antenna of the first embodiment has agrounded patch member 20 which is secured to a folded conductor thatincludes a further patch member 22 extending substantially parallel togrounded patch member 20 and also includes a radiating element 24. Thefurther patch member 22 has an aperture within which is positioned afeed patch member 26 that is connected to a feed probe 28. The feedprobe 28 is normally an extension of the center feedline of a coaxialcable (not shown) having its ground-line connected to grounded patchmember 20.

The antenna may be constructed such that the further patch member 22 andthe feed patch member 26 remain as a single piece of material while thefolded conductor is attached to grounded patch member 20 and feed probe28, and such that after the attachment a slot 30 is cut around the feedprobe 28 to define separated further and feed patch members. It is thecapacitance that results from presence of the slot that increases thebandwidth of the antenna.

Also illustrated in FIG. 1 are X, Y and Z axes that are used with FIGS.11, 12 and 13 to describe radiation patterns formed on the antenna.

Dimensions (in millimetres) of a typical example of the further and feedpatch members are shown in FIG. 2. In this example, further patch member22 is 45 mm long and 24 mm wide, whereas feed patch member 26 is 9 mmlong and 4 mm wide. Those portions of the slot 30 extending parallel tothe length dimension of the patch members are 1 mm wide, while thoseportions of the slot 30 extending parallel to the width dimension of thepatch members are 0.5 mm wide.

A second embodiment of the antenna, having a radiating element 24 not aswide as the length of the further patch member 22, is shown in FIG. 3.Adjusting the dimensions of the radiating element 24 in thisconfiguration allows both the frequency and bandwidth of the antenna tobe adjusted. The first and second embodiments exhibit, in general,wide-band characteristics. There are two resonances, the higher onebeing sufficient to provide coverage that extends over both the PCN andUMTS bands (1710 to 2175 MHz).

FIG. 4 illustrates a third embodiment of the antenna. The feed patchmember 26 is positioned such that one of its longer edges extendsin-line with one of the longer edges of the further patch member 22 onone portion of feed patch member 26. A radiating element 24 extendsbetween the grounded patch member 20 and the further patch member 26 onanother portion of further patch member 26. A feed pin 28 connects tofeed patch member 26.

FIG. 5 illustrates a typical surface current distribution for the firstembodiment of the antenna, and was created using a software simulationperformed for the higher, i.e. 1900 MHz and above, frequency bands. Forthis simulation, the height H of the further and feed patch membersabove the grounded patch member was set at 16 mm. The surface currentdistribution in FIG. 5 indicates that the feed probe was heavilyexcited, while the plate structure carried very low currents. Thisindicates that the probe was responsible for radiation from the antenna.FIG. 6 plots the return loss of the antenna, while FIG. 7 plots thesimulated real and imaginary impedance of the antenna over the samefrequency range. From these plots, it can be seen that the bandwidth,defined for a return loss of better than −10 dB is (2.17 GHz−1.61GHz)=560 MHz. This is equivalent to a “percentage bandwidth” of 29.5%,based on the calculation: (2.17−1.61)/{(2.17+1.61)/2}. The real part ofthe impedance is close to 50 ohms over that bandwidth, which makes iteasy to match the antenna to a communication system.

Four antennas, differing only in the length of the further patch member,were built for experimental measurement. FIG. 8 is a plot of the S11return loss versus frequency for the four antennas. As the further patchmember decreases in length from 45 mm to 30 mm, the bandwidth increasescorrespondingly. The maximum bandwidth, which was (2105 MHz−1375MHz)=730 MHz, i.e. percentage bandwidth of 42%, was associated with afurther patch member length of 30 mm.

FIGS. 9, 10 and 11 are vertical polarisation plots of the measuredradiation patterns in the respective polar azimuth XY plane, polarelevation XZ plane, and polar elevation YZ plane for the antenna of thefirst embodiment. These radiation patterns show good all-round coveragein the XY plane.

A parametric study was performed using the second embodiment of theantenna, having further and feed patch members with the dimensions (inmillimetres) shown in FIG. 12. The length of the further patch memberwas initially 45 mm, but was varied during the study. A radiationelement 16 mm high and 25 mm wide was initially used, but both heightand width were varied during the study. The probe had a radius of 0.6 mmand a length corresponding to the height of the radiating element. Thefurther and feed patch members were constructed as printed elements on aFR4 substrate having a thickness of 0.8 mm.

The parametric study involved varying in turn: (i) the length of thefurther patch member, (ii) the height of the feed pin and radiatingelement, and (iii) the width of the radiating element, while maintainingthe other parameters unchanged.

With respect to the length of the further patch member in the parametricstudy, FIGS. 13 and 14 illustrate respective variation of the imaginaryand real impedance with frequency as the length of the further patchmember reduces from 45 mm to 35 mm and then to 25 mm. Reducing the patchlength increased the lower resonant frequency slightly, from 800 MHz for25 mm to 970 MHz for 45 mm, but at the higher band the resonantfrequency remained nearly constant. FIG. 15 illustrates the change inS11 return loss with frequency for the three lengths of the furtherpatch member.

The effect of varying the height of the radiating element and length ofthe feed probe is plotted in FIG. 16 for a 50-ohm match impedance. Inthese measurements, the width of the radiating element was maintained at25 mm, and the length of the further patch member was maintained at 45mm. The height has a considerable impact on the resonances at bothfrequency bands. Resonant frequency increases at both bands as thelength of the feed probe reduces. The longer the probe length, the lowerthe frequency.

The effect of varying the width of the radiating element is shown inFIGS. 17 and 18, which respectively illustrate the imaginary and realimpedance of the antenna versus frequency for four radiating elementwidths. In these measurements, the height of the radiating element wasmaintained at 14 mm, and the length of the further patch member was;maintained at 45 mm. It was found that as the width of the radiatingelement was increased from 0 mm to 10 mm, then to 20 mm, and then to 25mm, the resonant frequency of the lower band increased. The resonantfrequency of the upper band remained relatively unchanged. A preferredreal and imaginary match was obtained for both bands when the width ofthe radiating element was 25 mm; real and imaginary match becomes betterfor the lower band as the radiating element is widened, but becomesworse for the higher band. An appropriate compromise is obtained at aradiating element width of approximately 25 mm.

FIG. 19 illustrates an antenna similar to that in the embodiment of FIG.4, except that the radiating element 24 is formed by a set of parallelstrips rather than a single piece of material. Regarding the parametricstudy mentioned above, varying the width of the radiating element formedof parallel strips produced approximately the same results as thoseshown in FIGS. 17 and 18 for the unitary radiating element. With respectto the radiating element formed of strips, references to ‘width’ meansthe distance separating outer edges of the outermost strips and includesthe width of gaps between the strips.

FIG. 20 illustrates a fifth embodiment of the subject invention. In thisembodiment, the feed patch member 26 is defined by the end of feed probe28. A capacitor 40 is connected between the end of the feed probe 28 andfurther patch member 22. In this embodiment, the bandwidth of theantenna is determined by the size of the capacitor.

FIG. 21 is a graph of the return loss (measured in dB) versus frequencyfor an antenna of the fifth embodiment when the capacitor 40 has a valueof 0.5 pF.

FIGS. 22 and 23 illustrate two variations of an alternative form of theinvention in which a grounded patch member, further patch member andfeed patch member all extend in the same plane. This form of theinvention is particularly suited to construction by etching a conductivesurface on a dielectric support. As shown in FIGS. 22 and 23, a groundedpatch member 50, a radiating element 52, a further patch member 54 and afeed patch member 56 are all formed by etching a conductive surface of adielectric support 58. A grounded portion of a coaxial cable 60 which isadapted to carry a feed signal is soldered to the grounded patch member50, and the feedline of the coaxial cable 60 is soldered to the end ofthe tail of the feed patch member 56. Sample dimensions are also shown(in millimetres) on FIGS. 22 and 23.

Referring again to FIG. 22, the dielectric support 58 may be formed fromany suitable non-conductive material, and FR4, polyester film, glass andduroid are usable. Depending on the material used for the dielectricsupport, some minor retuning of the radiating element 52 and the tail 56a of the feed patch member 56 may be required (the “tail” is theelongated portion of feed patch member 56 that extends parallel to theradiating element 52 in FIG. 22). The feed patch member tail 56 a andthe radiating element 52, both of which are formed by etching ofconductive material on the surface of the non-conductive support 58 orby printing onto the dielectric material of that support, are the mainradiating elements of the antenna at the lower frequency. The feed patchmember tail Sa acts as the radiating element at the higher frequencies.The gap shown in FIG. 22 between the further patch member 54 and thehead 56 b of feed patch member 56, which further patch member 54surrounds on three sides, is critical; that gap provides an impedancematch of the antenna to 50 ohms. That gap could be replaced by adiscrete capacitor; the capacitor value will depend on the applicationand installation.

The design shown in FIG. 22 may be employed in many applications.Typical installation requires the grounded patch member 50 to beconnected to a large metallic plate forming a ground plane. Theconnection could be in the form of a direct connection or capacitivecoupling. Capacitive coupling requires the ground plate to be positionednear to the metal area. For optimum performance, the antenna can beinstalled on a vehicle roof so as to be mounted vertically; thisarrangement, which is illustrated in FIG. 24, would normally be enclosedin a plastic cover. The antenna may be positioned proximate to a GPSantenna without any adverse effect on the latter. FIG. 25 illustratesthe antenna of FIG. 22 when installed on the glass of a car windscreen;it may be installed on any form of glass, for instance, on a front orrear windscreen, or a side window. A cable is connected to the feedpatch tail 56 a at 57. For optimum performance, any cabling of theantenna should be routed close to the car bodywork; this avoids unwantedradiation from the cabling. Mounting the antenna on a vehicle bumper isalso possible. In that case, the antenna can be produced on a standardprinted circuit board material and be installed such that the groundedpatch member 50 overlaps a metal reinforcement bar of the vehicle. Itshould be noted, however, that such low installation may result inantenna radiation being mainly directional at the lower frequencies.Other possible installation locations are: behind the rearview mirror,behind a side mirror, or even within a phone handset.

FIG. 26 illustrates the return-loss measurement in free space for theantenna of FIG. 22, and FIG. 27 the azimuth radiation pattern at a lowerfrequency of 960 MHz and higher frequency of 1795 MHz (both measured indBi) The graph in FIG. 28 illustrates return-loss results for aroof-mount installation of the antenna; to obtain these results, a largemetal plate was used to represent a car roof. FIGS. 29 and 30respectively represent radiation pattern measurements for lower andhigher frequency bands for the roof-mount antenna.

For optimum performance, the antenna is positioned a few millimetres offthe glass; this is a characteristic of the glass rather than theantenna. At frequencies such as 1.8 GHz, the glass acts as ahighly-lossy material, and positioning the antenna slightly away fromthe glass can reduce these losses. This is due to surface wavesgenerated on the glass, which waves do not radiate and are loss in thematerial. FIG. 31 respectively illustrates return-loss measurement foran antenna placed slightly away from the glass of a vehicle windscreen,and FIG. 32 illustrates radiation patterns measured in dBi for thatantenna (lower frequency of 890 MHz, and higher frequency of 1750 MHz).

As mentioned above, the antenna can be installed on a vehicle bumper,either at the front or rear, or optimally at both the front. FIG. 33illustrates the return-loss measurement for such an application, andFIGS. 34 and 35 illustrate corresponding radiation pattern measurementsfor a lower frequency of 925 MHz and an upper frequency of 1795 MHz,respectively.

Although the illustrated signal feed means in the antenna of FIG. 22 isthe coaxial cable 60, a coupled-line feed may be used instead.

FIGS. 36 and 37 illustrate an eighth embodiment of the antenna of theinvention. This embodiment is similar to the third embodiment of FIG. 4and the fourth embodiment of FIG. 19, but varies in the relativepositioning of the radiating element 70, the feed patch member 72, andthe feed pin 74, and in the position of those elements relative to thefurther patch member 76. The dimensions shown in FIGS. 36 and 37 are inmillimetres.

While the present invention has been described in its preferredembodiments, it is to be understood that the words which have been usedare words of description rather than limitation, and that changes may bemade to the invention without departing from its scope as defined by theappended claims.

Each feature disclosed in this specification (which term includes theclaims) and/or shown in the drawings may be incorporated in theinvention independently of other disclosed and/or illustrated features.

The text of the abstract filed herewith is repeated here as part of thespecification.

A high-bandwidth multi-band antenna includes a ground plane member, afirst patch member extending in generally-parallel spaced relationshipwith the ground plane member and electrically connected thereto, and asecond patch member connectable to a signal feedline and extendinggenerally coplanar with the first patch member within a slot formed inthe first patch member. The second patch member is formed integral witha vertical conductive connecting member as part of a folded conductingplate; this construction allows the second patch member to be quicklyand accurately positioned relative to the ground plane member beforeattachment to the ground plane member. The antenna has the advantages ofa high bandwidth, simple construction and inexpensive manufacture.

1-35. (canceled)
 36. A high-bandwidth multi-band antenna comprising agrounded patch member, a further patch member extending ingenerally-parallel spaced relationship with the grounded patch memberand being electrically connected thereto by a radiating element, and afeedline capacitively coupled to the further patch member.
 37. Ahigh-bandwidth multi-band antenna comprising a grounded patch member, afurther patch member extending in generally-parallel spaced relationshipwith the grounded patch member and being electrically connected thereto,and a feed means adapted to carry a feedline signal, the feed meansterminating generally coplanar with the further patch member andoccupying part of a void space in the further patch member, a slot beingthereby defined between the further patch member and the termination,the further patch member and the termination being capacitively coupledacross the slot.
 38. The antenna as described in claim 37, wherein thefeed means is a feed patch member, and wherein dimensions of the feedpatch member and the width of the slot are selected such that each iswithin a respective range in which the bandwidth of the antenna varieswith the slot width.
 39. The antenna as described in claim 37, and alsocomprising a discrete capacitor connected between the feed means and thefurther patch member.
 40. The antenna as described in claim 38, whereinthe further patch member is electrically connected to the grounded patchmember by a radiating element extending between the grounded patchmember and one first edge of the further patch member.
 41. The antennaas described in claim 40, wherein a first edge of the radiating elementia connected to the one first edge of the further patch member.
 42. Theantenna as described in claim 40, wherein the feed means extendsinwardly from an unconnected portion of the one first edge of thefurther patch member.
 43. The antenna as described in claim 40, whereinthe further patch member and the radiating element are integrally formedfrom a conductive sheet and separated by a fold-line in the sheet. 44.The antenna as described in claim 38, wherein the grounded patch member,the further patch member and the feed patch member are each formed as aconductive surface on a dielectric support.
 45. The antema as describedin claim 43, and also comprising a solid dielectric material extendingin the space that separates the grounded patch member from the furtherpatch member and the feed means.
 46. The antenna as described in claim38, wherein the further patch member and feed patch member both have arectangular shape with longer first edges af each being oriented in thesame direction.
 47. The antenna as described in claim 46, wherein afrequency bandwidth for a higher one of the resonant frequencies of theantenna increases with a reduction in the length of the further patchmember.
 48. The antenna as described in claim 46, wherein a lowestresonant frequency of the antenna decreases with a reduction in thelength of the further patch member.
 49. The antenna as described inclaim 40, wherein the resonant frequencies of the antenna increase withan increase in the width of the radiating element.
 50. The antenna asdescribed in claim 40, wherein the radiating element is comprised of aseries of parallel strips, each strip extending between the groundedpatch member and the one first edge of the further patch member.
 51. Theantenna as described in claim 36, wherein the antenna operates in afirst band in the range of 900 MHz and in a second band in the range of1800 MHz.
 52. The antenna as described in claim 51, wherein the antennaalso operates in a third band in the range of 2200 MHz.
 53. The antennaas described in claim 38, and also comprising a radiating elementconnecting a portion of an edge of the grounded patch member to aportion of an edge of the further patch member such that the groundedpatch member, radiating element and further patch member form agenerally U-shaped configuration, wherein the grounded patch member,further patch member, feed patch member and radiating element all extendin the same plane.
 54. The antenna as described in claim 53, and alsocomprising a feedline patch member connected to the feed patch member,the feedline patch member extending generally parallel to the radiatingelement and toward the grounded patch member in the plane of the furtherpatch member, feed patch member and radiating element.
 55. The antennaas described in claim 54, wherein the grounded patch member, furtherpatch member, feed patch member, feedline patch member and radiatingelement are each formed as a conductive surface on a dielectric support.